Question

Which seismic waves can travel through the liquid medium?
A) Primary waves
B) Secondary waves
C) Surface waves
D) Oceanic waves

Answer 1

Hint: It is an elastic body wave, which can propagate through solids, liquids and gases. It is the fastest seismic wave and reaches the seismograph before its other two counterparts. It is also described as the first signal of an earthquake. It is also called pressure waves, i.e. formed from alternating contractions and rarefactions.

Complete answer:
Seismic Waves are energy waves that propagate through the earth. These can be caused due to earthquakes, volcanic eruptions, magma movement, explosion, landslides etc. These waves consist of a primary wave (P-wave), secondary wave (S-wave) and surface wave.

Now let us look into the given options:
Option A) Primary Waves – these waves are also known as P-waves, and they are longitudinal in nature. They travel faster than other waves through the earth and reach the seismograph stations first and hence they are called ‘primary’. It can travel at 5000 m/s in solids, 1450m/s in liquids and 330m/s in air. Thus, this option is correct.
Option B) Secondary Waves – These are also called S-waves and are transverse in nature. They are slower than P-waves. These waves can only travel through solids. They cannot travel through liquids and gases as they cannot support shear stress. They also do not travel through the magma and the mantle and the core of the earth. Thus, this option is incorrect.
Option C) Surface Waves – There are waves that travel through the earth’s surface during an earthquake. It only travels on solids and causes vibration on the earth’s surface. These waves cause huge waves in the oceans. These waves can cause liquids to move but not travel through them or through air. Hence, this option is incorrect.
Option D) Oceanic Waves –They are the waves that form in the seas and oceans and are a result of seismic waves or a result of the wind flowing over them. Oceanic waves are not seismic waves at all. Hence, this option is also incorrect.

Thus, the correct answer is Option (A) i.e, Primary Waves.

Note: The seismic waves can be recorded by seismometer on land and with a hydrophone in water. A seismometer response the shaking of the ground and its noises. It is combined with a timing device and a recording device to form another device called seismograph, which is used to measure the intensity of waves and detect earthquakes. The output that this device produces is called a seismogram.